拔节期光强对水稻抗倒伏能力的影响及机理

摘要

[目的]探讨拔节期光强对水稻Oryza sativa L.抗倒伏能力的影响.[方法]通过人工气候箱光强控制试验,在基部第1、第2、第3节间伸长期及第1~3节间伸长期进行不同光强处理,测定水稻茎秆倒伏指数和基部节间的形态和材料力学性状.[结果]倒伏指数随着光强增加显著下降.在第1~3节间伸长期连续用中、高光强处理,茎秆倒伏指数比低光强处理降低34.8%~73.9%.倒伏指数与节间长度呈极显著正相关,与节间粗度、茎壁厚度和节间充实度呈显著负相关.第2节间伸长期是茎秆抗倒伏能力对光强反应最敏感的时期.光强对水稻抗倒伏能力的影响有累积效应.第1~3节间伸长期连续处理条件下,倒伏指数和多数形态、材料力学性状的变异系数高于单个节间伸长期处理.[结论]节间长度、茎壁厚度和节间充实度是影响茎秆抗倒伏性的关键因子.光强改变了节间长度、单位体积节间干质量和茎壁厚度等形态特性,进而影响茎秆抗折力和弯曲力矩等材料力学性状,最终影响水稻抗倒伏能力.%[Objective]To explore the effects of light intensity during internode elongation on rice (Oryza sativa L.) lodging resistance.[Method]Rice plants were subjected to different light intensities in phytotrons at the 1st (S1), 2nd (S2), 3rd (S3) and 1st to 3rd (S123) internode elongation stages. The lodging resistance of rice stem and the morphological and material mechanical traits of basal internodes were measured.[Result]The lodging index (LI) of rice stem significantly decreased with the increasing of light intensity. LI of medium or high light intensity treatments was 34.8%–73.9% lower than that of low light intensity treatment at the S123 internodes elongation stage. LI was significantly positively correlated with internode length, and negatively correlated with internode diameter, culm wall thickness and internode plumpness. The S2 stage was the most sensitive period of lodging resistance to light intensity variation. Light intensity had accumulative effects on lodging resistance. The variation coefficient of lodging index at the S123 stage was greater than those at the S1, S2 and S3 stages, and similar results were found in most morphological and material mechanical traits.[Conclusion]The key factors to determine the lodging resistance are internode length, culm wall thickness and internode plumpness. Light intensity can significantly change the three morphological traits of basal internodes, which further affect the material mechanical characteristics of rice stem and lodging resistance.